In article <4012a910@news.povray.org>, wwi### [at] gmxde says...
> Christopher James Huff wrote:
> 
> >> Basically, the patch allows you to select a rectangular region of
> >> an image_map so that only this part is read in and stored in RAM.
> >> Pixels outside this region are all considered 50% gray (some other
> >> solution like quick_color could also be thought of).
> > 
> > Pixels outside that region should probably be fully transparent, to be
> > consistent with the "once" option. 
> >
> I would prefer the pixels to be of configurable color...
Considering that 'color' can be rgbf <1,1,1,1>, I would have to agree 
there. You want transparent, make it transparent. lol

> 
> > And why not read in the region as the
> > entire image, filling the entire area of the image_map? Simpler, and
> > avoids the above problem completely.
> > 
> I do not completely understand what you plan there but it seems to me 
> that this requires the used to do additional scaling and 
> rotation/translation of the texture (which may not be trivial for 
> some projections). 
> Furthermore, for my current personal use, the 50% gray is a "feature" 
> (sea level on Mars). 
However, I agree with Christopher's view that actually clipping the image 
completely, instead of filling the rest of a color, could be better for 
some uses. Like an actually image map, instead of the what you are doing 
with it. It wouldn't necessarily require extra scaling and the like, 
since in this case you would be using the clipped region as though it was 
the complete image, so in some situation like an animation you just move 
the clipping you plan to do in the direction you want and that becomes 
the new image. POV-Ray would save memory a lot by only loading the region 
piece of the image it actually needs, instead of the whole thing.

I am still not 100% sure what you are actually doing in the case of your 
patch, the only explanation you give is a vague reference to "(sea level 
on Mars)", which doesn't say if you are using it as a) and image map, b) 
a height field, c) some other thing... You might have better luck 
convincing people that filling the image, instead of simply clipping is 
better, if we had an example of what you are doing with it. ;)

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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